Why 19mm and 30mm focal lengths for new Sigma lenses?

I must be missing something but I cannot understand why Sigma would come out with slightly wide and slightly tele lenses for it's entry into the M43 market. Why not a true wide angle say a 12mm and a 25mm or 50mm? The lenses appear to be very good ( see Ephotozine ). If they had come out with a 12mm that good, I would have snapped one up.